In the construction industry and more generally in respect of powered tools and equipment, such as a powered drill or a powered saw, it is desirable to prevent accidental or unauthorized operation of the tools and equipment. Further, it is desirable to prevent or inhibit theft of such tools and equipment, which is a known problem in the construction industry where inefficiencies result if workers must constantly gather and lock up their tools and equipment in a safe storage location whenever a construction site is left unattended.
Applicant is aware of various means in the prior art which preclude unauthorized or accidental operation of a power tool. For example, there exists in the prior art electronic systems for control of power tools involving secret codes, where numeric codes are used in such devices rather than a mechanical key. The difficulty with such prior art mechanisms is that they are generally complex and intricate, and thus expensive to manufacture and incorporate into a power tool. Further, the electrical switch within a power tool is generally located within the power tool casing, making prior art devices that interact with the electrical switch difficult to install given space constraints.
It is therefore an object of the current invention to provide a means to disable a power tool and dissuade theft without resorting to locking the tool in a toolbox or other locked location, or running cables or chains combined with padlocks in and around the power tool. With the present invention, it is possible to have a locking mechanism permanently attached to the power tool that will not obstruct its use hence providing the opportunity to lock the tool at any time.
It is a further object of the present invention to provide for a locking device integral to the power cord of the power tool, rather than the electrical switch within the power tool.
It is a still further object of the present invention to provide an economical means to render a power tool inoperable and whose simplicity is such that it may attached to power tools as a retro-fit after-market addition by the user rather than needing to be incorporated into the power tool during manufacturing.
It is still a further object of the present invention to provide a locking device for a power tool that is designed to automatically render the tool inoperable after the expiry of a preset time period.
A further object of the present invention is to provide a built in safety feature, that unlike prior art, requires a separate key to be placed into the lock and turned in order to operate the electric tool, wherein, in a preferred embodiment, the key may then be removed once turned while still leaving the tool operable so long as plugged into a mains power supply. Prior art of which applicant is aware includes Canadian Patent No. 2,283,552 which issued Oct. 3, 2001 to St. Pierre for an Activation Code and Ownership Identification System for Power Tools, PCT Application No. PCT/GB00/03939 Internationally Filed Oct. 12, 2000 to Prize-man for Controlling Electrical Machines, DE Patent No. 100 29 138 issued Jan. 3, 2002 to Ferdinand for Locking Device for Prevention of Use of Hand-Tool Equipment, includes Electronic Lock Containing a Secret Code, EP Patent No. 0 674 973 published Oct. 14, 1995 for an Electric Tool with a Coding Means for its Activation, GB Patent No. 2 353 323 published Feb. 21, 2001 to Tumball for Access Control to Electrical Machines, GB Patent No. 2 405 559 published Mar. 3, 2005 to United States Patent Application Publication No. 2003/0062250 published Apr. 3, 2003 to Kraenzler et al. for an Electric Hand Power Tool with Switching Key, United States Patent Application Publication No. 2003/0136652 published Jul. 24, 2003 to Bascom et al. for Lockout Mechanism for Power Tool, United States Patent Application Publication No. 2004/0020670 published Feb. 5, 2004 to Kusmierski et al. for Switch Lock-off Mechanism for Power Tools, United States Patent Application Publication No. 2005/0035659 published Feb. 17, 2005 to Hahn et al. for Electronic Key for an Electrical Apparatus and Electrical Apparatus with Receiver for an Enabling Signal, U.S. Pat. No. 3,571,544 issued Mar. 23, 1971 to Sheehan for Magnetic Key Operated Switch for Electrically Operated Hand Tools, U.S. Pat. No. 3,632,914 issued Jan. 4, 1972 to Osika for Key-Operated Electrical Switch, U.S. Pat. No. 4,359,615 issued Nov. 16, 1982 to Meyerboefer et al. for Switch and Means to Prevent Unauthorized Operation Thereof, and U.S. Pat. No. 5,736,837 issued Apr. 7, 1998 to Noda for Battery Charging Device for Battery Driven Tool.
The prior art generally teaches the use of a second button, keypad or lever that must be operated or engaged prior to the tools main switch for the power tool to operate. This prior art method works well when an authorized user is working the electric tool, however fails to completely stop an unauthorized user such as a child from working out how to start the electric tool, for example by observing the keypad code entered by the authorized user. With the lockdown device installed and in the off, that is, disabling position, the electric tool is unable to be operated even though the electric tool is in the possession of the unauthorized user. Unlike in the prior art, electric tools accessible to unauthorized users such as children may be made inoperable by use of the present invention and thus cause little threat, the present invention may be retro-fit to existing power tools, and render them both inoperable and difficult to tamper with to remove the present invention without damaging the tool, thereby rendering the tool unattractive to a would-be thief.